Manufacturing vinyl halides



Patented Dec. 12, 1939 MANUFACTURING VINYL HALIDES mum, Rhe'lnielden in Baden, Germany, as signer -to I. G. Farbenlndustrle Aktiengesellsehalt, Franktort-on-the-Maln, Germany No Application May 25, 1938, Serial" No. 209,984. In Germany May 28, 1937= 8 Chimp (Cl. 260656) The present invention relates to an improved process for manufacturing vinyl halides. It has been shown," for instance, in British Patent No. 21,134 of 1913 that the product oi! addition or hydrogen halide to acetylene may be obtained by allowing the gases to bubble through a solution of a catalyst which is preferably maintained at a temperature some degrees below the boiling point of the solvent. when this process 10 is applied on a large scale there are considerable disadvantages. I1, for example, a mercury salt is used as the catalyst it volatilizes with the vapor oi! the solvent and there is very soon a diminution of the active catalyst so that finally the reaction comes to rest. A iurther disadvantage is that the mercury salt suilers reduction to metallic mercury.

Now, I haveiound that the said disadvantages may be avoided so that. the reaction between no acetylene and hydrogen halide with the use of a mercury salt as a catalyst may be carried out as a permanent, operation when using an anhydrous liquid carrier for the catalyst which on the one hand is a sufficiently good solvent for the 5 mercury salt and on the other hand is also capable of dissolving alkali halides or the double salts which they form with mercury compounds, for instance, HgCl2.2NaCl,' HgClaZKCl. Suitable organic solvents of this kind are the aliphatic m-glycols of low molecular weight and their halohydrins. These may be kept anhydrous and permit the operation to proceed at vthe necessary high temperature. I

It has further been found that the activity of the catalyst may be essentially prolonged-ii. there is added to a solution containing the catalyst a salt of such a heavy metal which forms several stages of oxidation, preferably a cerium salt, and ii care is taken thatthe hydrogen halide contains a small proportion of tree halogen.

, 'The following example illustrates the invention: I

In 1000 parts by weight of anhydrous glycol there are dissolved about 40 to 50 parts of mercuric chloride, 25 parts of potassium chloride and 1 1 part of anhydrous cerium chloride. This solution is saturatedwithdry hydrogen chloride'and there is passed through the solution, which may be circulated ina tower, at a raised temperature ofabout 90 to about 100? C. and in'countercurrent to the catalyst dry acetylene and dry halogen chloride in the proportion by volume ofv 4:5. The gases produced then contain to per cent. by volume of vinyl chloride.

- During the 66 operation there may be added to the hydrogen chloride introduced about'0.1 per cent. by volume of chlorine. The reaction maybe conducted as a continuous process without degradation oi. the catalytic action.

Obviously,-my invention is not limited to the 5 foregoing example or to the'speciflc details given therein. Thus, for instance, instead of glycol methyl-, di-methylor ethylglycol, glycerine, glycerine-a-chlorohydrin or similar compounds of this series may be used as a solvent. The merm curic chloride-potassium chloride double salt may be substituted by either mercuric chloride alone or, by the double salt formed with an earth alkali halogenide.

What I' claim is:

1. In a process for manufacturing a vinyl halide by the addition or hydrogen halide to acetylene in the presence of a mercuric halide, the step which comprises reacting the said components in the presence 01' an organic solvent of so low molecular weight of the group consisting of polyhydric aliphatic alcohols and the halohydrins thereof, in which the mercuric halide is dissolved.

2. In a process for manufacturing a vinyl halide by theaddition of hydrogen halide to 8@ acetiylene in the presence of a'inercury com pound, the step-which comprises reacting the said components in the presence of an organic solvent of low molecular'weight of the group consisting of polyhydric aliphatic alcohols and a 'the halohydrins thereof, in which a mercuric compound of the group consisting of a double salt of mercuric halide with an alkali halide and an alkaline earth halide-is dissolved.

3. In a process for manufacturing a. vinyl M halide by the addition of hydrogen halide to acetylene in the presence of a mercuric halide, the

step which comprises reacting the said compo-. nents in the presence of an organic solvent of low molecularweight of the group consisting of w polyhydric aliphatic alcohols and the halohydrins thereof, in which the mercuric halide is dissolved, and of a salt of a heavy metal capable oi. more than one stage of oxidation.

4. In a process for manufacturing a vinyl halide by the addition of hydrogen halide to acetylene in the presence of a mercuric halide, the step which comprises reacting the said components in the presence of an organic solvent oi low molecular weight of the group consisting w of polyhydric aliphatic alcohols and the halohydrins thereof, in which the mercuric halide is dissolved, and of cerium chloride.

5. In a process formanufacturing a vinyl halide by the addition of hydrogen halide to 55- acetylene in the presence of a mercury compound, the step which comprises reacting the said components in the presence 01' an organic solvent of low molecular weight of the group consisting of polyhydric aliphatic alcohols and the halohydrins thereof, in which a mercuric compound of the group consisting of a double salt of mercuric halide with an alkali halide and an alkaline earth halide is dissolved, and of ceri- .um chloride.

7. In a process for manufacturing a vinyl.

halide by the addition of hydrogen halide to acetylene in the presence of a mercury compound, the step which comprises reacting the said components in the presence of an organic solvent of low molecular weight of the group consisting of polyhydric aliphatic alcohols and the halohydrins thereof,' in which a mercuric compound of the group consisting of a double salt of mercuric halide with an alkali halide and an alkaline earth halide is dissolved, and of cerium chloride, the hydrogen chloride containing minimal amounts of free chlorine.

8. The process which comprises dissolving about 40 to about 50 parts of mercuric chloride, 25 parts of potassium chloride and 1 part of anhydrous cerium chioride in 1000 parts of glycol, saturating the solution with dry hydrogen chlo- .ride, and contacting it with a gas mixture com- KARL JUNG. 

